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  • 1
    Electronic Resource
    Electronic Resource
    Oxidative aminomercuration of 2-propyn-1-ols. Stereoselective syntheses and structures of cis-[1,4]oxazino[3,2-b]-1,4-oxazine derivatives (1986)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 119 (1986), S. 887-899 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Oxidative Aminomercurierung von 2-Propin-1-olen. Stereoselektive Synthese und Struktur von cis-[1,4]Oxazino[3,2-b]-1,4-oxazin-DerivatenDie Reaktion von 2-Propin-1-olen 1 mit 2-Aminoalkoholen 7 in Gegenwart von Quecksilber(II)-chlorid beginnt mit einer oxidativen Aminomercurierung, gefolgt von hoch stereo-selektiven Reaktionsschritten, die zu cis-[1,4]Oxazino[3,2-b]-1,4-oxazin-Derivaten 10 führen. Nach den Röntgenstrukturanalysen von 10c,f,g zeigen diese Verbindungen die gleiche Anordnung um die zentrale Bindung, und zwar so, daß die anomere Stabilisierung ein Maximum erreicht.
    Notes: The reactions of 2-Propin-1-ols 1 with 2-amino alcohols 7 and mercury(II) chloride start with an oxidative aminomercuration step followed by a series of highly stereoselective processes leading to cis-[1,4]oxazino[3,2-b]-1,4-oxazine derivatives 10. X-Ray analyses of 10c,f,g show that these compounds have the same geometrical arrangement around their central fusion bond in such a way that anomeric stabilisation reaches a maximum.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19861190313
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  • 2
    Electronic Resource
    Electronic Resource
    Metallacyclodisiladiazanes of Titanium and zirconium; Synthesis, Structure and Polymerization Studies (1997)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 130 (1997), S. 399-404 
    Details
    ISSN: 0009-2940
    Keywords: Disilylamides ; Group 4 Complexes ; Polymerization ; Metallacycles ; Titanium ; Zirconium ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A series of metallacyclodisiladiazanes has been prepared. Lithiated (SiMe2NHtBu)2 (1) reacts with TiCl4 · 2 THF to give (SiMe2NtBu)2TiCl (4). Methylation or fluorination of 4 leads to (SiMe2NtBu)2TiMe2 (8) and (SiMe2MtBu)2TiF2 (9), respectively. The reaction of ZrCl4 · 2 THF with lithiated 1 or [SiMe2NH(4-FC6J4)]2 (2) yields (SiMe2NtBu)2ZrCl2 (5) and [SiMe2N(4-FC6H4)]ZrCl2 · THF (7), respectively. The lithiated ligand [SiMe2NH(2,6-iPr2C6H3)]2 (3) reacts with noncoordinated ZrCl4 to give [SiMe2N(2,6-iPr2C6H3)]2ZrCl2 (6). X-ray structural analysis of 9 showed it to be a fluorine-bridged dimer in the solid state. Compounds 4, 6, 8 and 9 were found to be catalysts for the polymerization of ethylene.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19971300314
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  • 3
    Electronic Resource
    Electronic Resource
    Iminophosphorane-mediated synthesis of mesoionic 1,3,4-Oxadiazolo-[3,2-a]pyridinylium-2-aminides (1988)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 121 (1988), S. 1495-1500 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Iminophosphoran-vermittelte Syntheses von mesoionischen 1,3,4- Oxadiazolo[3,2a]pyridinylium-2-aminidenDas Iminophosphoran 2 reagiert mit Methylisocyanat zu dem mesoionischen 1,3,4-Oxadiazolo[3,2-a]pyridinylium-2-methylaminid 3, das durch CF3SO3CH3 zum 1,3,4-Oxadiazolo[3,2-a]-pyridinium-Kation 4 methyliert wird. Struktur 4 wurde durch Röntgenstrukturanalyse gesichert. Durch Einwirkung von Base lagert das mesoionische Aminid 3 zum isomeren mesoionischen 1,3,4-Triazolo[3,2-a]pyridinylium-2-olat 11 um. Verbindung 3 wird durch (Arylimino)triphenylphosphorane in die entsprechenden 1,3,4-Oxadiazolo[3,2-a]pyridinium-2-arylaminide 12 umgewandelt, die auch aus Iminophosphoran 2 und Hydroximoylchloriden zugänglich sind.
    Notes: Reaction of iminophosphorane 2 with methyl isocyanate yields the mesoionic 1,3,4-oxadiazolo[3,2-a]pyridinylium-2-methylamindie 3, which undergoes N-methylation with CF3SO3CH3 to give the 1,3,4-oxadiazolo[3,2-a]pyridinium cation 4. The structure of compound 4 has been established by means of X-ray crystallography. Mesoionic aminide 3 undergoes rearrangement by the action of base to give the isomeric mesoionic compound 1,3,4-triazolo[3,2-a]pyridinylium-2-olate 11. Compound 3 by the action of (arylimino)triphenylphosphoranes is converted into the corresponding 1,3,4-oxadiazolo[3,2-a]pyridinylium-2-arylaminides 12, which can be also prepared from iminophosphorane 2 and hydroximoyl chlorides.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19881210825
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  • 4
    Electronic Resource
    Electronic Resource
    Heterocyclization Reactions of Conjugated Heterocumulenes. Synthesis of Pyridine Derivatives by a Tandem Aza Wittig/Electrocyclization Strategy (1989)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 122 (1989), S. 307-313 
    Details
    ISSN: 0009-2940
    Keywords: Aza Wittig reaction ; Heterocumulenes, conjugated ; Pyridine derivatives ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Cyclisierungsreaktionen von konjugierten Heterocumulenen. Synthese von Pyridinderivaten durch Tandem-Aza-Wittig/Elektro-Ringschluß-StrategieDie Aza-Wittig-Reaktion der Iminophosphorane 3 mit Isocyanaten führt zu konjugierten Carbodiimiden 4, die elektrocyclisch 2-Pyridincarbonsäureester 5 ergeben. Iminophosphoran 9 reagiert mit Nitromethan bzw. Aceton im Molverhältnis 1:1 zu 10 bzw. 11. Aus 9 und Nitromethan 1:3 entsteht das Iminophosphoran 12. Dessen Struktur wurde durch Kristallstrukturanalyse bewiesen. Die Iminophosphorane 10, 11 reagieren mit Isocyanaten oder Kohlendioxid zu den Pyrazolo[3,4-b]pyridinen 13, 15 bzw. 14, 16.
    Notes: The aza Wittig reaction of iminophosphorane 3 with isocyanates leads to conjugated carbodiimides 4, which undergo electrocyclic ring closure to give ethyl 2-pyridinecarboxylates 5. Iminophosphorane 9 reacts with nitromethane and acetone in a 1:1 molar ratio to form 10 and 11, respectively. Reaction of 9 with nitromethane in 1:3 molar ratio yields the iminophosphorane 12. The structure of 12 has been established by X-ray crystallography. Iminophosphoranes 10 and 11 react with isocyanates or carbon dioxide to give the pyrazolo[3,4-b]pyridines 13, 15 and 14, 16, respectively.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19891220217
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  • 5
    Electronic Resource
    Electronic Resource
    Synthesis, Characterization and Dynamic Behavior of (π-Allyl)palladium Complexes with Polydentate Nitrogen Ligands, Evidence of a Dissociative Mechanism (1996)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 129 (1996), S. 589-594 
    Details
    ISSN: 0009-2940
    Keywords: Fluxionality ; Heterocyclic ligands ; Palladium complexes ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: New examples of the fluxional behavior of (η3-allyl)palla-dium complexes are described. Variable-temperature experiments and line-shape analysis of two (η3-allyl)palladium complexes containing 2-(1H-pyrazol-1-yl)azine ligands were performed in order to determine the activation free energies, enthalpies and entropies of the process. A dissociative mechanism pointing to a selective Pd-N cleavage is proposed on the basis of these results and NOE experiments above and below the coalescence temperature.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19961290519
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  • 6
    Electronic Resource
    Electronic Resource
    Synthesis, Structure and Conformation of cis- and trans-(μ-1,6-Dimethylheptalene)bis(tricarbonyliron) (1996)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 129 (1996), S. 1569-1572 
    Details
    ISSN: 0009-2940
    Keywords: Heptalenes ; Carbonyliron complexes ; cis and trans complexation ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The reaction of 1,6-dimethylheptalene (2) with Fe2(CO)9 affords two binuclear iron complexes 4a and 4b, each bearing two tricarbonyliron moieties, in trans and cis orientation, respectively. The reaction leads additionally to the formation of the monocomplexed compound 3. NMR studies indicate that the heptalene moiety of the new compounds is a π-bond isomer of 2, and this is clearly attributable to steric factors. Single-crystal X-ray structure analyses of the metal complexes 4a and 4b confirm that the Fe(CO)3 fragments adopt trans and cis geometries, respectively, with respect to the plane of the carbocycle. The ring systems of the two isomers adopt different conformations in the solid state. In the case of 4a, a hitherto unknown chair-like conformation is determined, whereas in complex 4b the ring system shows a twisted double boat conformation.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19961291226
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